I have a Linksys WRT54g router as my gateway to the Internet as well as having it handle WiFi and my other hard-wired devices. Off of port #4 I have a Linksys RTP300 router with 2 Voip phones connected.

I use the WRT54g with a 3rd party firmware (Alchemy) to manage QoS. Basically I tell it that port #4 has a higher priority than all the other ports.

I have had no issues so far. I have only been a customer for about 20 days though....